High energy tube forming means



Feb. 4, 1964 J. P. ORR 3,120,259

HIGH ENERGY TUBE FORMING MEANS Filed May 15 1961 2 Sheets-Sheet 1 INVENTOR. JAMES P. ORR

J. P. ORR

HIGH ENERGY TUBE FORMING MEANS Feb. 4, 1964 2 Sheets-Sheet 2 Filed May 15, 1961 INVENTOR. JAMES P. ORR

141m & 16mm United States Patent 3,120,259 HIGH ENERGY TUBE FORMING MEANS James P. Orr, Lfieside, Calii, assiguor to The Ryan Aeronautical (30., San Diego, Calit'. Filed May 15, 1961, Ser. No. 110,843 6 Claims. (Cl. 15379) The present invention relates generally to metal working and more particularly to high energy tube forming means.

The primary object of this invention is to provide means for shaping or forming the ends of tubes by an explosive charge, the apparatus being usable on tubes already assembled into structures and in confined spaces.

Another object of this invention is to provide tube forming means which is completely self-contained and is sufi'iciently compact to be assembled and operated in a space very little larger than the unit itself.

Another object of this invention is, to provide tube forming means containing a of parts and which is held together by a single locking element.

A further object of this invention is to provide tube forming means in which a basic charge holding and clamping assembly is used with interchangeable die elements shaped to form the tube as required.

Finally, it is an object to provide tube forming means of the aforementioned character which is simple and convenient to manufacture and operate and which will give accurate and consistent results.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specification, particularly pointed out in the claims, and illustrated in the drawings which form a material part of this disclosure, and in which:

FIGURE 1 is an exploded longitudinal sectional view of the complete apparatus;

FIGURE 2 is a sectional view of the apparatus attached to a tube;

FIGURE 3 is an end elevation view as taken from the left end of FIGURE 2;

FIGURE 4 is a sectional view taken on the line 44 of FIGURE 2; and

FIGURE 5 is a sectional view taken on the line 55 of FIGURE 2, but showing a difierently shaped die.

Similar characters of reference indicate sinul 'ar or identical elements and portions throughout the specification and throughout the views of the drawing.

General Structure Referring now to FIGURES 1-4 of the drawings, the apparatus includes a mandrel .10 having an axial bore 12 to receive a cartridge 14, a firing head 16, a pair of die halves 18 and 2%, a clamp collar 22 and a locking ring 24. The cartridge 14 is loaded into one end of the mandrel 10, the other end of bore 12 being closed and the bore having vents 26 which open radially into an annular channel 28 cut in the mandrel. The die halves 18 and 2% together comprise a generally cylindrical body split diametrically and are internally bored to receive t. e mandrel 19 axially therebetween, said mandrel having an enlarged end 30 which seats in a corresponding groove 32 in the die halves so that the mandrel is clamped tightly against axial displacement. The die halves are also bored to receive the firing head 16 which is held in close abutment against the cartridge holding end of mandrel It The firing head having a retaining flange 34 fitting into a groove 36 in the die halves. For convenience, the groove in die half 18 is extended into an open slot 3-8, allowing removal of the firing head 16 3,120,259 Patented Feb. 4, 1964 from the side, so facilitating insertion of cartridge 14 after the unit is assembled.

The die halves ;18 and 20 together have a threaded portion 40 at the end containing firing head 16, the other end being a tapered, substantially conical portion 42 diverging from the threaded portion. Internally the die halves are undercut to provide a shaped cavity 44 corresponding to the required shape of the finished itube end, the cavity being in axial alignment with the channel 28 in mandrel 10 and the end of said cavity adjacent the firing head comprising a stop shoulder 46. Extending from the cavity 44, the die halves have an open bore 48 substantially the external diameter of the tube 50, which is to be formed, the mandrel 10 having a plug end 52 which fits into the tube, as in FIGURE 2. An O-ring 54, or similar sealing means, is fitted to the plug end 52 to prevent pressure loss.

The clamp collar 22 is a simple cylindrical collar having a tapered bore 56 corresponding to the taper of the conical portion 42 and clamps the die halves tightly together by an axial wedging action. The clamp collar 22 is held in place by the locking ring 24, which is internally threaded to screw on the threaded portion 40 and may be provided with sockets 58 to receive a spanner wrench or the like for tightening.

In the firing head '16 is an axially disposed firing pin 69 positioned to strike the detonator portion of cantridge l4, and extending radially therefrom is an actuating pin 62 which forces the firing pin into the cartridge by a cam action of the tapered end 64 thereof. This arrangement avoids blowback by eliminating any direct axial outlet from the cartridge through the firing head. However, other firing means may be used, either mechanical or electrical, that illustrated being merely an example.

Operation The mandrel it) is placed between the die halves 18 and 20 which are then inserted into the clarnp collar 22, the locking ring 24 being started on the threaded portion 40 to hold the assembly loosely together. The tube 50 is then inserted into the bore 43 until abutting against the stop shoulder 46, after which the locking ring 24 is advanced to clear the open slot 38. The cartridge 14 is then inserted and the firing head 16 slipped into place, the locking ring 24 then being fully tightened to clamp the assembly firmly. The ability to insert the firing head from the side after assembly of the unit on the tube delays loading of the cartridge until the final stage and so eliminotes the danger of inadvertent firing due to careless handling. To facilitate insertion of the tube 50, the initial threads of the threaded portion 40 may be made slightly undersize, the resulting looseness in the preliminary assembly allowing slight separation of the die halves.

When the cartridge 14 is fired, the resultant gases exhaust through the vents 26 into the channel 28, the extremely high pressure produced driving the end of the tube 5% into the cavity 44. The shape of the tube end conforms precisely to the shape of cavity 44, the accurate results of explosive or high energy forming being well known.

Leakage of gases into the tube is prevented by the O-ring '54, so preventing damage to the interior of the tube or anything connected thereto. If additional protection is required, a thin plastic sleeve, not shown, may be inserted into the tube before forming. After forming the locking ring 24 is loosened and the apparatus removed :from the tube.

Variations in Structure The assembly illustrated in FIGURE 5 is similar in all respects to that described above except for the die halves, one die half 68 being shown and the other removed,

Ad vanta ge's Due to the simplicity of the apparatus, assembly and disassembly can be carried out rapidly, a desirable feature in production loperations. The compactness of the unit makes it possible to attach the unit to a tube in a confined space, as Within the structure indicated in broken line in FIGURE 2. The unit is pre-assembled in loose form before attachment and requires only the tightening of the locking ring 24 when installed in place. Normally, tube ends are formed before assembly and clearances must be allowed for the enlarged vportions, While in some instances it may be impractical to preform the tubes, in frwhich case special elaborate tube connectors must be used. The present apparatus eliminates the need for such procedures. Various types and sizes of cartridges may be used according to the forming pressure required. The apparatus is safe to use in confined spaces and will provide'consistently accurate results without the need for elaborate setting up and alignment.

The operation of this invention will be clearly comprehended from a consideration of the foregoing description of the mechanical details thereof, taken in connec tion with [the drawing and the above recited objects. It will be obvious that all said objects are amply achieved by this invention.

It is runderstood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that the specification and drawing are to be considered as merely illustrative rather than limiting.

I claim:

1. energy tube forming means, comprising:

a mandrel;

a source of high pressure *gases carried by said mandrel; V

a split die having a bore to receive a tube to be formed;

said die having an internal shaped cavity in said bore corresponding to the required shape of the formed tube;

said die having an externally threaded portion at one end and an externally tapered portion diverging from said threaded portion;

an intern-ally tapered clamp collar encircling said die at said tapered portion;

a threaded locking ring on said threaded portion and being adjustable to clamp said die within said collar;

said ring and collar clamping the die on the mandrel;

said mandrel having gas conducting vents providing communication from said source to said cavity;

and means to initiate high pressure gas flow from said source.

2..High energy tube forming means, comprising:

a mandrel having a central bore to receive an explosive cartridge, a split die internally cut to enclose and retain said mandrel;

said =die having an externally threaded portion at one end and an externally tapered portion diverging from said threaded portion; an internally tapered clamp collar encircling said die at said tapered portion; a threaded locking ring on said threaded pontion and being adjustable to clamp said die within said collar; an open bore in said die to receive a tube to be formed; said die having an internal shaped cavity in said tube 4. receiving bore corresponding to the requiredshape of the formed tube;

said mandrel having vents from said central bore opening into said shaped cavity;

and means to fire a cartridge contained in said central bore.

3. High energy tube forming means, comprising:

a mandrel having a central bore to receive an explosive V cartridge, a split die internally cut to enclose and retain said mandrel; said die having an externally threaded portion at one end and an externally tapered portion diverging from said threaded portion; an internally tapered clamp collar encircling said die at said tapered portion; a a threaded locking ring on said threaded portion and being adjustable to clamp said die Within said collar;

an open bore in said die to receive a tube to be formed;

said die having an internal shaped cavity in said tube receiving bore corresponding to the required shape of the formed tube;

said mandrel having vents from said central bore opening into said shaped cavity; sealing means on said' mandrel for sealed connection with a tube to be formed;

a firing head abutting said mandrel and being retained 'by said die;

and firing means in said firing head to tire a cartridge contained in said central bore.

4. High energy tube forming means, comprising: 7

a mandrel having a central bore to receive an explosive cartridge;

a split die internally cut to enclose and retain saidmandrel;

said die having :an externally threaded portion'at'one end and an externally tapered portion diverging from said threaded portion;

an internally tapered clamp collar encircling said .die

at said tapered portion;

a threaded locking ring on said threaded portion and being adjustable to clamp said die Within said collar;

an open bore in said die to receive a tube to be formed;

said die having an internal shaped cavity in said tube receiving bore corresponding to the required shape of the formed tube;

said mandrel having a plug portion extending into and concentric with said open bore;

sealing means on said plug portion for sealed connection with a tube to be tormed;

said mandrel having vents from said central bore opening into said shaped cavity;

and means to fire a cartridge contained in said central bore.

5. High energy tube forming means, comprising:

a mandrel having a central bore at one end to receive an explosive cartridge;

a split die internally cut to enclose and retain said mandrel;

said die having an externally threaded portion at one end and an externally tapered portion diverging from said mandrel having vents from said central bore opening into said shaped cavity;

and means to fire a cartridge contained in said central bore.

6. High energy tube forming means, comprising:

a mandrel having a central bore lat one end to receive an explosive cartridge;

a split die internally cut to enclose and retain said mandrel;

said die having an externally threaded portion at one end and an externally tapered portion diverging from said threaded portion;

an internally tapered clamp collar encircling said die at said tapered portion; a threaded locking ring on said threaded portion and being adjustable to clamp said die within said collar; an open bore in said die to receive a tube to be formed; said die having an internal shaped cavity in said tube receiving bore corresponding to the required shape of the formed tube;

said mandrel having a plug portion extending into and concentric With said open bore;

sealing means on said plug portion for sealed connection with a tube to be formed;

said mandrel having vents from said central bore opening into said shaped cavity;

said die having a transverse groove in said threaded portion;

said groove having an open slot at one side and a firing head radially insertable and removable from the side without dismantling the die.

References Cited in the file of this patent UNITED STATES PATENTS 939,702 Jones Nov. 9, 1909 2,038,304 Middler Apr. 21, 1936 3,031,007 Temple et al Apr. 24, 1962 

1. HIGH ENERGY TUBE FORMING MEANS, COMPRISING: A MANDREL; A SOURCE OF HIGH PRESSURE GASES CARRIED BY SAID MANDREL; A SPLIT DIE HAVING A BORE TO RECEIVE A TUBE TO BE FORMED; SAID DIE HAVING AN INTERNAL SHAPED CAVITY IN SAID BORE CORRESPONDING TO THE REQUIRED SHAPE OF THE FORMED TUBE; SAID DIE HAVING AN EXTERNALLY THREADED PORTION AT ONE END AND AN EXTERNALLY TAPERED PORTION DIVERGING FROM SAID THREADED PORTION; AN INTERNALLY TAPERED CLAMP COLLAR ENCIRCLING SAID DIE AT SAID TAPERED PORTION; A THREADED LOCKING RING ON SAID THREADED PORTION AND BEING ADJUSTABLE TO CLAMP SAID DIE WITHIN SAID COLLAR; SAID RING AND COLLAR CLAMPING THE DIE ON THE MANDREL; SAID MANDREL HAVING GAS CONDUCTING VENTS PROVIDING COMMUNICATION FROM SAID SOURCE TO SAID CAVITY; AND MEANS TO INITIATE HIGH PRESSURE GAS FLOW FROM SAID SOURCE. 